Mobile wireless communication devices, such as a cellular telephone or a wireless personal digital assistant, can provide a wide variety of communication services including, for example, voice communication, text messaging, internet browsing, and electronic mail. Each of these applications can have different service requirements for operating characteristics, such as performance parameters for delay latency, packet loss and jitter tolerance. Providing the capability to ensure an end to end quality of service (QoS) characteristic for an application can prove challenging, as packets can traverse multiple independent nodes between the mobile wireless communication device and a destination end point. Setting QoS characteristics within an IP network can be accomplished by managing link bandwidths to achieve an acceptable packet loss rate. Increasing transmission capacity between nodes can lower the packet loss rate; however, on a wireless access network, with limited radio frequency bandwidth shared by multiple users, implementing QoS can require prioritizing packets into different flows, each flow having different transmission characteristics. Matching higher layer application level QoS requirements to lower layer transmission level flows can ensure packets receive appropriate treatment when traversing the wireless access network.
IP networks were originally designed for best effort delivery of data that could tolerate indeterminate delay and packet loss. More recently, QoS models for IP networks have been developed including a differentiated services model that can provide QoS for connections through an IP network. A User Datagram Protocol (UDP) checksum field can be included in a UDP header attached to UDP data and encapsulated in an IP datagram at a source endpoint. Additionally, the IP datagram can include an IP header. Routers along a connection path can read the IP header to determine how to handle the IP packet to provide a QoS as specified in the IP header. The IP header can provide a convenient “in band” method of signaling for processing units, such as routers, that operate using higher layer protocols.
Processing units that operate using lower layer protocols can treat the IP header as data only. Not all equipment through which the IP packet passes can read the IP header, and thus alternative methods of providing differentiated treatment for the IP packet by network components operating at the link layer can use “out of band” signaling methods. In particular, wireless transceivers included in mobile wireless communication devices can treat the entire IP packet, including the IP header, as a data payload without reading any of its contents. Separate mechanisms can be required by the wireless transceiver to ensure IP packets received from a source application are accorded appropriate QoS treatment by the wireless transceiver at the link layer. These separate mechanisms can prove cumbersome. The UDP checksum field contained in the UDP header can be considered optional and unused by higher layer protocols. The UDP checksum field can thus be available to use for communication between processing units within the mobile wireless device. The UDP checksum field can be used separately from or in conjunction with the IP header to provide in-band signaling methods that can be more efficient than out of band signaling methods.
Thus there exists a need to classify and prioritize packets at both the network and link layers automatically by the mobile wireless communication device using the UDP checksum field.